#不同等级的道路的速度
def convert(highway):
    if (highway == 'primary' or highway == 'primary_link'):
        return 50
    elif (highway == 'secondary' or highway == 'secondary_link'):
        return 40
    elif (highway == 'tertiary' or highway == 'tertiary_link'):
        return 30
    elif (highway == 'trunk' or highway == 'trunk_link'):
        return 60
    elif (highway == 'service' or highway == 'residential' or highway == 'rail_link' or highway == 'unclassified'):
        return 15
    else:
        return 15